Revision is vitally important. The aim is to memorise the information and be able to recall it on demand and apply it to unfamiliar exam questions.
A little and often, planned approach, that forces you to interact with the information you need to remember is best. Just reading information over and over is some help, but there are better ways. Everybody learns differently, some people can remember what they are told, others prefer to read it/see it, others like to handle the information. The process of creating revision materials is as important and useful as using them.
Doing practice papers helps you get familiar with the layout and demands of the exam – understanding what the command/key words used in the questions mean/are asking for, knowing how marks are given for the parts of answers, being able to use quotes and graphs… all helps you maximise your chance to get the best grade possible.